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JPY750 Million for Gallium-Oxide Power Devices

March 22, 2017 by Jeff Shepard

Flosfia Inc. has announced that it has raised ¥750 million from several existing and new investors including strategic ones. Flosfia is aiming to commercialize Corundum Structured Gallium Oxide (α-Ga2O3) in order to revolutionize power electronics. The company will use this capital to develop its own production lines and commence commercial production of the world's first α-Ga2O3 600V TO-220 diodes in 2018.

For example, last August Flosfia has developed a gallium oxide-based diode with the world’s lowest on-resistance, at 0.1 milliohms per square centimeter. Energy loss can be reduced by 85 percent compared to silicon carbide (SiC) based diodes, which have an on-resistance of 0.7 milliohms per square centimeter.

The anticipated superiority of Flosfia’s gallium-oxide devices stems from the material’s approximately 5–electron-volt bandgap—way higher than that of gallium nitride (about 3.4 eV) or silicon carbide (about 3.3 eV). Bandgap is a measure of the energy required to kick an electron into a conducting state. A bigger bandgap enables a material to withstand a stronger electric field, making it possible to use a thinner device for a given voltage. That’s important because the thinner the device, the lower its resistance, and thus the more efficient it is.

Gallium-oxide devices do not excel in all areas. One drawback is poor thermal conductivity. Another downside is that the crystal quality is not as high when grown on a sapphire substrate as it would be using a gallium-oxide substrate, which at the moment is quite expensive. GaN and SiC devices, on the other hand, are already cost and performance competitive with silicon devices in a growing number of applications.

Underwriting companies in Flosfia’s second round of funding include: Miyako Capital., Ltd.; Energy & Environment Investment, Inc.; The University of Tokyo Edge Capital Co., Ltd. (UTEC); Nissay Capital Co., Ltd.; Yaskawa Electric Corporation; Kyoto University Innovation Capital Co., Ltd and Future Venture Capital Co., Ltd..